The invention relates to an apparatus and method for holding and mechanically releasing a pump down means, such as a ball or wiper plug element, such as during cementing operations of a subterranean oil or gas well or during other oil and/or gas operations.
As a step in the completion operation of a subterranean well, a casing is run into the well and the annular area exterior of the casing and within the open bore thereafter is cemented to secure the casing within the well. Cementing plugs, wiper balls, ball elements, and other pump down means are utilized in the cementing operation and are run ahead and behind the cement slurry in order to wipe mud off the walls of the casing or drill pipe and to prevent cement from being contaminated with the drilling fluid previously circulated within the casing and the well. Such plugs are often run into the well within the casing and behind a cement slurry in order to wipe the casing inner diameter and close off check valves, open stage collars, and close again stage collars during multi-stage cementing operations, and the like.
In the past, the connection between a cementing swivel and top drive unit has been broken, and a pump down means which is larger than the internal diameter of the drill string, and larger than the opening of the box end connection, has been inserted into the drill string using physical force, such as by beating the pump down means with a hammer, and then the cementing swivel is reconnected to the top drive unit, and afterwards the pump down means is pumped downhole. This prior art method suffers from the disadvantage of damaging the box end threads, damaging the pump down means, and further limiting the maximum size for the pump down means which is “beat” into the drill string.
While certain novel features of this invention shown and described below are pointed out in the annexed claims, the invention is not intended to be limited to the details specified, since a person of ordinary skill in the relevant art will understand that various omissions, modifications, substitutions and changes in the forms and details of the device illustrated and in its operation may be made without departing in any way from the spirit of the present invention. No feature of the invention is critical or essential unless it is expressly stated as being “critical” or “essential.”